docs: add Notification section to SECURITY.md (#24926)
docs: add Notification section to SECURITY.md (#24926)

adds a new section pointing to a relevant doc in Governance that defines how we notify end-users of security issues.
gerhardberger/electron,electron/electron,seanchas116/electron,bpasero/electron,seanchas116/electron,gerhardberger/electron,bpasero/electron,electron/electron,gerhardberger/electron,bpasero/electron,electron/electron,seanchas116/electron,electron/electron,gerhardberger/electron,seanchas116/electron,gerhardberger/electron,gerhardberger/electron,bpasero/electron,bpasero/electron,electron/electron,seanchas116/electron,electron/electron,seanchas116/electron,bpasero/electron,bpasero/electron,electron/electron,gerhardberger/electron